Apparatus for producing crown closure



June 19, 1956 G, HAMMOND, JR 2,750,910

APPARATUS FOR PRODUCING CROWN CLOSURE Filed Feb. 18, 195o 2 sheets-sheet1 GEORGE HAMMOND JR ,3m a. Mn

June 19, 1956 G, HAMMOND, JR

APPARATUS FCR PRODUCING CROWN CLOSURE 2 Sheets-Sheet 2 Filed Feb. 18.1950 3 vw cam/tofu GEORGE HAMMOND JR- abby/tu APPARATUS FOR PRODUCINGCRWN CLSURE George Hammond, Jr., Manheim Township, Lancaster County,Pa., assigner to Armstrong Cork Company, Lancaster, Pa., a corporationof Pennsylvania Application February 18, 1950, Serial No. 145,010

2 Claims. (Cl. 113-42) This invention relates to crown closures andtheir manufacture and more particularly to a method and apparatus forproducing closures of this type on double-action presses.

This application is a continuation-in-part of my copending application,Serial No. 65,825, filed December 17, 1948, now abandoned, which is acontinuation-in-part of application Serial No. 18,013, filed March 30,1948, now abandoned.

In the production of crowns on a double-action press, a metal blank iscut from sheet stock on the closing action of the press. This cut blankis held momentarily between the two die assemblies, after which it isformed to the proper configuration by the action of a forming ram whichtravels down through the movable die assembly and forms the cut blankover the forming die. This forming operation is accomplished on thesecond action of the press. The cutting die is actuated by a cammechanism which is so designed as to provide a dwell at the bottom ofthe stroke to hold the female die member in its lowermost positionduring the forming operation. The forming ram is actuated by a crankwhich imparts reciprocating motion to the ram head. It will beunderstood, of course, that the crank may be replaced by an eccentric orother means to impart reciprocating motion to the ram. Single-actionpresses have been used to a minor extent in the production of crownclosures. In a press of this type the cutting punch and forming die arepositioned in the top or movable part of the press and the blanking andforming operation is carried out on a single stroke of the press. On thedownward or closing action of the press, the cutting punch shears ametal blank from the sheet stock placed over the female die member. Thiscutting punch and forming die continue their downward path of travel andbend the metal blank down over a stationary forming head affixed to thebottom platen of the press. In a single-action press, the cut-out blankis held between the cutting and forming die combination and a drawingring which surrounds the stationary forming head. This drawing ring isurged downwardly by the cutting punch and forming die against-a spring,rubber cushion, or other resilient means disposed in the lower portionof the press assembly. v

It will be clear to those skilled in the art of metal cutting andforming that the double-action press has many advantages over asingle-action press. One chief advantage is derived from the shortstroke requiredv in the double-action press. Inasmuchas the cutting andforming operations are carried out separately, the power re'- quired foreach operation is less than is required for the combined operation on asingle-action press. It is, therelfore-possible to accomplish this workby a shorter stroke of the press; and consequently, the equipment can beoperated at a faster rate than a single-action press.

wniteci States Patent 'i Patented June 19, 1956 ice Another advantage isderived from the accurate adjustment on the cutting and forming toolswhich can be attained and maintained on a double-action press inasmuchas the tools are all adjusted by positive means. On a single-actionpress, the drawing ring is working against a spring, rubber cushion, orother resilient means which have a tendency to become fatigued duringcontinual use of the press; and therefore, close adjustment of thedrawing ring cannot be maintained. The above are some of the chiefreasons why it has been common practice in the closure industry toproduce crown closures on doubleaction presses.

In most cases, the crown blanks are cut from tin plate which has beenpreviously lithographed with a suitable decoration. The design of thedouble-action presses currently used in the production of crown closuresis such that the tin plate is necessarily placed in the press with thelithographed or exterior surface down in engagement with the stationarydie assembly located in the bottom platen of the press. The cutting ofthe blank is accomplished by shearing of the metal between the innercircumference of the female die member and the outer circumference ofthe male die member as the dies are brought together. In a shearingaction of this kind, the die having the larger cutting diameter, whichis the female die member, bends the metal away from the innercircumference of the die and curls the metal around the die memberhaving the smaller cutting diameter. This curling action forms afinished blank having a rounded edge on the side which has been cut bythe female die member.

In crown forming tools used prior to this invention for producing crownson double-action presses, the circular die having the larger cuttingdiameter engaged the decorated or exterior surface of the tin plate and,consequently, formed a rounded edge on the exterior or decorated side ofthe blank.

The purpose of this invention is to provide a method and apparatus forproducing crowns having a rounded edge on the bottom surface. One of thechief advantages to be derived from a crown having the bottom edgerounded is that it will flow more freely in the chutes of bottle-cappingequipment and also in the crown assembly equipment.

It has also been found that crowns having a rounded edge on the bottomsurface do not scratch and mar the decorated surface of other crownswhen they are packaged for shipment or storage. Due to the configurationof crown closures, they have a tendency to nest when packaged. With therounded edge provided on thesev new crowns, the possibility of scratchesto the decoration resulting from this nesting is negligible.

To achieve the desired results described above, I have developed'sheetmetal cutting tools adapted for use in the conventional double-actionpresses common to the closure industry in which the die having thegreater cutting diameter contacts the interior or undecorated surface ofthe crown blank and, therefore, rounds the edge of the interior surfaceof the crown rather than the edge of the exterior surface.l

' In order that my invention maybe more readily understood, the samewill be described in connection with the attached drawings in which:

Figure 1 is a cross-sectional view of a press assembly .showing thetools in position inv an open press;

'.Figure 2 `is a cross-sectional view similar to Figure l showingthepress closed with'a cut blank positioned between the two sets of dies;.-.I Figure 3 is va cross-sectional view similar to Figure l showingthezp'ress closed `with a in' the die assembly;

formed crown in position' Figure 4 is an isometric view of the cuttingpunch and forming die assembly of my invention;

Figure 5 is an isometric view of the forming die;

Figure 6 is a cross-sectional view showing the position of the formingdie within the male cutting punch;

Figure 7 is an enlarged cross-sectional view of a portion of a finishedcrown closure; and

Figure S is an enlarged cross-sectional view of a portion of a cutblank.

Referring to Figures l, 2, and 3, there is shown a male die assembly 2and a female die assembly 3. The male die assembly 2 comprises a cuttingpunch 4, a crown forming and crimping die 5, and an ejector assembly 6,said ejector assembly comprising an ejector sleeve 7 and an ejector 8.The forming and crimping die 5 rests on the top surface of an adjustingsleeve 9 and is secured thereto by means of a split collar il which titson a ri-ange E?. on the bottom of the forming and crimping die 5 andflange i3 on the top of adjusting sleeve 9 which is in threadedengagement with the die shoe 10. This collar 11 permits movement of theforming and crimping die 5 in a direction parallel to the direction oftravel of the press head but it does not prevent the forming andcrimping die 5 from rotating or moving slightly in a directionperpendicular to the direction of travel of the press head. The reasonfor this movement will be explained more fully hereinafter. The circularcutting punch 4 surrounds forming and crimping die 5 and rests onshoulder 1d of the die shoe lo. A stripper plate 15 is providedsurrounding the cutting punch 4, but is not in engagement therewith. Thepurpose of this stripper plate 15 is to remove the skeleton, from whichthe blanks have been cut, from its engagement with the center surface ofthe cutting punch 4.

The female die assembly 3 is made up of die member 16 which is adaptedto cooperate with the cutting punch 4 to shear the blank. The female diemember 16, after it has sheared the blank, overlaps and surrounds thecutting edge of the cutting punch 4 while the crown is being formed tofinal configuration. Positioned within this female die member 16 is aholding sleeve 17, the upper portion of which tits snugly into thefemale die member i6; however, the lover portion of the outer surfacethereof is cut out, leaving an opening 18 between the holding sleeve i7and the female die member 16. This opening is preferably about .030" inwidth and extends about .75 along the side of the holding sleeve 17. Thepurpose of this opening is to collect dirt and excess lacquer removedfrom the tin plate, thus preventing an accumulation of the same at thelower surface of the holding sleeve 17. This opening is automaticallycleaned by the constant running of the machine jarring the materialloose. This holding sleeve 17 does not extend down as far as the bottomof the female die member lo, leaving a small recess 19 which isapproximately the same diameter as the blank to be cut from the tinplate. This recess is slightly deeper than the thickness of theblank tobe cut so that the blank will not be lirmly clamped between the male andfemale die members. The holding sleeve 17 is locked in place in thefemale die member f6 by means of a locking pin 2t) which tits intocompanion grooves in the female die member i6 and the holding sleeve 17.This locking pin 20 serves only to hold the holding sleeves in place butis not the sole means for preventing the upward movement of the hildingsleeve, such upward movement being prevented by the shoulder 21 of thefemale die member which engages the top surface of the holding sleeve.The holding sleeve i7 is free to rotate with respect to the female diemember i6.

Operating within the holding sleeve 17 is a forming ram 22 which movesdownwardly, and in cooperation with forming and crimping die, shapes thecrown to its nal configuration.

On the closing or cutting action of the press, the male die assembly 2remains stationary and the female die assembly is moved into engagementtherewith, so that the sheet metal positioned between the two assembliesis sheared by the cutting edge 23 of the male cutting punch 4 and thecutting edge 24 of the female die member 16. The clearance between thesetwo cutting edges should be such that proper shearing action isobtained.

Figure 2 of the drawing shows the die in closed posi tion with the cutblank 25 in position between the two die assemblies. The skeleton fromwhich the blank 25 has been cut is shown at 26. The arrangement of partsillustrated in Figure 2 shows the position of the various elements ofthe assembly at the completion of the first action of the double-actionpress.

Figure 3 shows the position of the elements after the completion of thesecond action ofthe double-action press. It will be noted from theexamination of Figure 3 that the forming ram 22 has been forceddownwardly against the blank 25 and has forced the blank down over theforming die 5, thus forming it to the desired configuration. The ejectorsleeve 7 and the ejector 8 are forced down by the action of the formingram 22. The ejector sleeve 7 compresses a spring in the bottom of thepress assembly, not shown, and the ejector 8 compresses spring 27 in thecenter of the ejector sleeve 7. Upon the withdrawal of the forming ram22, the ejector sleeve 7 and the ejector 8 are returned to theiroriginal position as shown in Figure 1.

To insure the proper formation of the crown, it is essential that therelative position of the forming die 5 with respect to the cutting punch4 be properly adjusted. In assembling the component parts of the dieassembly, the male cutting punch 4 is press fitted into the die shoe 10and held firmly therein by means of a set screw not shown. The formingdie 5 is then placed inside the cutting die 4 and its height is properlyadjusted by means of adjusting sleeve 9 which is in threaded engagementwith the die shoe l0.

For best results it has been found desirable to adjust the forming die 5so that its highest portion is about .030 above the top surface of thecutting punch 4. With an adjustment of this kind, the downward movementof the female die member will tend to iiex the metal blank 25 slightlydownward around its perimeter. When the downward movement of the femaleassembly 3 stops, the blank is held between the holding sleeve ll7 andthe forming die 5, but not between the holding sleeve 17 and the topsurface of the cutting punch 4. Since the forming die 5 has a relativelysmall top surface area for engagement with the under or decoratedsurface of the blank 25, the possibility of marring the decorationduring the forming operation is slight. Also the limited area ofclamping between the holding sleeve 17 and the forming die 5 issufiicient to hold the blank 25 in the proper position for the formingoperation but insuiicient to prevent slippage so that the blank can beactually formed by bending rather than drawing.

As another precaution to prevent marring and scratch ing of thedecoration, the top surface of the cutting punch 4 and the forming die 5have been specifically designed. The design of these two elements isshown in Figures 4, 5, and 6. From an observation of these figures, itwill be apparent that the inner circumference of the top edge of themale cutting punch 4 is rounded and also the outer circumference of thetop edge of the forming die 5 is rounded to eliminate sharp edges in thearea over which the metal moves. The rounded edge of the cutting punch 4is designated by the numeral 28, and the rounded edge on the forming die5 is shown at 29. These rounded edges are clearly shown in Figure 6. Therounded edge 2S on the cutting punch 4 permits the metal which is forcedthrough the grooves 30 on the forming die 5 to start its downward pathof travel before the outer rim of the blank actually reaches the grooves30 of the forming die 5. -The metal which is formed over the projections31 of the forming die continues to move in a substantially horizontaldirection regardless of the rounded edges 28 and 29.

In the preferred embodiment, the cutting punch 4and the forming andcrimping die 5 are made as separate units so that the cutting punch canbe removed from the assembly for sharpening without the necessity ofgrinding the surface of the forming and crimping die 5 and so that theforming die 5 can be properly positioned with respect to the cutting die4.

For most satisfactory operation, the outside diameter of the forming die5 should be about .015 less than the inside diameter of the cuttingpunch 4. This clearance permits the forming die 5 to move slightly in alateral direction to facilitate the forming ram 22, centering itself inthe forming die 5. This movement is necessary in gang set-ups of thetype commonly used in the manufacture of crown closures, because throughconstant usage there is a tendency for the forming ram and forming dieto get out of alignment. This oating movement of the forming die 5permits the die to move slightly and properly align itself with theforming ram. This materially aids in the producing of a more uniformlyformed crown, as it overcomes the possibility of the ram exerting morepressure on one side of the blank than on the other.

Because of this floating action, it is desirable to make the wallthickness of the forming die 5 greater than the wall thickness of thecutting punch 4, because the lateral stress caused by the forming ram 22entering the forming die 5 must be withstood by the forming die 5.

In designing the tools for use in carrying out my invention, it isessential that the top surfaces of the forming die 5 and the bottomsurface of the holding sleeve 17 be normal to the longitudinal axis ofthe die assembly. This is necessary so that the cut-out blank 25 will beheld by a uniform pressure around its circumference. If desired, thebottom edge of the female cutting die 16 can be ground to a slight taperso that the circumference of the blank is sheared progressively ratherthan instantaneously.

Figure 7 shows a cross section of a portion of the fmished crown showingthe rounded edge 34 on the interior of the crown.

Referring to Figure 8, there is shown to exaggerated scale a cut blank25 having a film of decorating paint 33 applied thereto. This View showsthe rounded edge 34 which is on the side of the blank opposite the sideto which the decorating paint has been applied.

In the operation of the device of my invention, a sheet of suitablemetal such as tin plate having a decoration applied to one side thereofis placed on the stripper plate 15 with the decorated surface down. Thefemale die assembly 3 which is in alignment with the male die assembly Zmoves downwardly and the blank is sheared by the cutting edge 23 of themale die member 4 and the cutting edge 24 of the female die member 16.The female die member continues its downward movement for a shortdistance and overlaps the male die member, completely surrounding thecutting edge thereof as shown in Figure 2. At this phase of theoperation, the cut blank is held between the bottom edge of the holdingring 17 and the top surface of the forming die 5. Immediately after theblank has been cut, the forming ram 22 contacts the undecorated surfaceof the blank and, in cooperation with the forming and crimping die 5,forms the blank to the desired configuration. During this formingoperation, the holding sleeve prevents the edge of the metal blank frombending upwardly. Since the edge cannot bend upwardly, the downwardaction of the ram 22 forces the metal over the serrations of the forming`and crimping die and forms the closure to the desired configuration.

After the completion of the forming operation, the fe male die membermoves upwardly away from the male die member and the formed crown isejected from the forming and crimping die 5 by the ejector rod 8. Theskeleton from which the blank has been cut is then removed from the maledie member by means of the stripper plate 15 which is actuated by meansnot shown.

It will be clear from the foregoing description that I have developed amethod and apparatus for producing crown closures in which the bottomedge of the finished crown will be rounded by the action of the femalecutting die member which shears the blank. The tools covered by thisapplication are adapted to fit the conventional double-action presscurrently used in the productiorrof crown closures in the industry. Itis not necessaryl to change the pressV mechanism, and the conventionaltools may be reinserted in the press without necessitating anyalterations.

I claim:

1. In a die set for shearing and forming crown closure shells andsimilar articles from sheet material in a doubleacting press, thecombination of a hollow punch; a hollow forming member disposed withinsaid punch having a forming surface on the inner periphery thereof, saidhol low punch being provided with an external severing edge on the outerperiphery thereof and a rounded edge in the inner periphery adjacent theouter edge of said forming member, the position of said forming memberwith respect to said punch being such that the top surface of theforming member terminates in a plane above the top surface of saidpunch; a hollow die having an internal severing edge on the innerperiphery complementary to the severing edge of said punch when saidpunch is disposed within the said die to sever a blank from a sheet ofmaterial disposed between the punch and die upon the closing action ofsaid press, with the outer periphery of the blank having a slightlycurved surface extending toward the severing edge of the punch; a hollowclamping member disposed within said die and secured thereto; a clampingsurface on said clamping member complementary to the top surface of saidhollow forming member for slip-gripping the blank therebetween when thepress is closed; and a forming ram, said ram being disposed within saidclamping member and being movable with respect thereto to a positionbelow said clamping member and within the said hollow forming member toengage a limited area of said blank on the side opposite the sideengaged by the forming member to bend the same over said forming surfaceto form an article of the desired configuration upon the second actionof said press, the outer diameter of the forming die being less than theinner diameter of the hollow punch to permit the forming die to centeritself with respect to the forming ram.

2. In a die set for shearing and forming crown closure shells andsimilar articles from sheet material in a doubleacting press, thecombination of a hollow punch; a hollow forming member disposed withinsaid punch having a forming surface on the inner periphery, the outerdiameter of said forming member being substantially the same as theinner diameter of the punch, said hollow punch being provided with anexternal severing edge on the outer periphery thereof and a rounded edgeon the inner periphery adjacent the outer edge of said forming member,the position of said forming member with respect to said punch beingsuch that the top surface of the forming member terminates in a planeabove the top surface of said punch; a hollow die having an internalsevering edge on the inner periphery complementary to the severing edgeof said punch when said punch is disposed within said die to sever ablank from a sheet of material disposed between the punch and die uponthe closing action of said press, with the outer periphery of the blankhaving a slightly curved surface extending toward the severing edge ofthe punch; a hollow clamping member disposed within said die and securedthereto; a clamping surface on said clamping member complementary to thetop surface of said hollow forming member for slip gripping the blanktherebetween when the press is closed; and a forming ram, said ram beingdisposed within said clamping member and being movable with respectthereto to a position below said clamping member and within the saidhollow forming member to engage a limited area of said blank on the sideopposite the side engaged by the forming member to bend the same oversaid forming surface to form an article of the desired configurationupon the second action of said press.

References Cited in the le of this patent UNITED STATES PATENTS OpsalMar. 2, 1909 8 Adriance etal June 11, 1912 Elsner July 2, 1918 BohleOct. 16, 1923 Carter Dec. 19, 1933 Ho'thcrsall Apr, 6, 1937 MacCokrdyApr. 13, 1937 Plumb Oct. 24, 1939 Wareham Aug. 5, 1941

